Storefront Sill Bracing 2

[XR250]

I am doing the light gage design on a structure with storefront systems as shown (see attached). As you can see, if I frame up cripple studs under the window, there is nothing to brace my sill track on the left side. Usually, the EOR has specified cantilevered tube steel to brace the sill, but not on this job. I could cantilever up some cripple studs using moment clips at the slab but these are expensive, labor intensive and the stiffness is questionable. I am thinking about just throwing it back in the storefront supplier's lap and having his system provide bracing for the left end of the sill. Thoughts?

 

[Teguci]

I'd think the storefront guy doing this would make the most sense. The right side of the door is a already a continuous element from floor to top, he may just need to reinforce it. Not sure how the paper trail needs to happen though.

 

[XR250]

That is what I thought. I will just clearly note it on my drawings and let the arch/GC hash it out. If I send an RFI, I will be sitting on these for weeks.

 

[Ron]

Throw it back to the EOR. He/She is responsible to provide adequate formation to accomplish a delegate design.

 

[XR250]

Thank you Ron. On most of the metal stud jobs I do, the EOR has rarely thought about "adequate formation".
Funny, I have been doing jobs in NC for most of career but have recently started doing jobs in the DC area in the last five years. The drawings coming out of those northern areas seem to be alot worse with regards to the metal stud framing. Must be a cultural thing up there :>

 

[jayrod12]

I would bet the storefront guy has already (or would) size the mullions as if the lower portion was part of his scope. I know I would.

 

[XR250]

I hope so - otherwise it is going to be a fight. The metal stud subs are always low man on the totem pole.

 

[dhengr]

XR250:
I suspect that Ron meant ‘adequate foundation’ or primary structure, not “adequate formation.” “The metal stud subs are always low man on the totem pole,” should not be the case. Pick up the damn phone and talk to the Arch. &/or EOR to be sure they correct this discrepancy, and do the proper coordination with the door/window supplier, and provide for your needs, since you really can’t fix it, given the way they detailed things. Then also put the note on your drawings, with big lettering. I’m really sick and tired of the way things are being designed and built these days. Everything is subbed out and delegated, to the point that nobody is really responsible for anything any longer. You do your thing, I do mine, and never the two shall meet or interact, the two parts never get coordinated until they get out on the job and don’t fit together, or work together. We are doing so much texting and e-mailing these days that we don’t have time to actually communicate, and more better BIM won’t fix this.

 

[sandman21]

It depends on how the contract is setup, if the stud are not part of the EOR's responsibility then no details will be shown and the delegated engineer is responsible for providing support for the system based on the loading provided. I will bet that the EOR to provide metal stud support for the sill using Simpson MSSC connectors or similar product.

 

[Teguci]

@ sandman21:
Consider that, per the contract documents, the Light Gage Metal Guy (LGMG)is responsible for the design of the light gage, non-load bearing, exterior wall and has included calculations and connection details for the EOR to review. In those calculations/shop drawings, the LGMG has provided connections and the transfer of loads to the storefront system. In my mind, that kind of detail is very much the responsibility of the EOR. What does the contract drawing show, probably a typical detail of a wall section. Maybe a typical wall to storefront detail, but it is unlikely that this detail was handled where the cripple wall ends against a door frame. The entire building is the responsibility of the EOR. The EOR has the authority, and therefore, the responsibility, to correct this problem.

 

[XR250]

"foundation" "formation" you say tomato I say tomahto :>


Thanks for the all the advice. I have to pick my battles on this one as I have already had the EOR add a bunch of other stuff that he missed. I am running up on the deadline so I am going to show it on my drawings with the studs braced against the storefront with a big note and let them hash it out. My experience has been that EOR's do not like to add steel after the fact as they are worried about having to pay for it.

The whole process is backwards. Metal studs should be delegated, but it should be by the owner, EOR or Arch and engineered concurrently with the A&E drawings so all of these details can hashed out before the job gets bid. There would be tons of opportunities for savings as the subs would not have to throw a bunch of money into the bid unforeseen stuff.

 

[sandman21]

If the design is delegated than the drawings will most likely not show this condition and the responsibility of the design of the metal stud to support the sill and storefront. If the EOR is doing the design than everything should be shown.

When a design is delegated the EOR's responsibility is the structure used to support the delegated design.

 

[XR250]

If the design is delegated than the drawings will most likely not show this condition and the responsibility of the design of the metal stud to support the sill and storefront. If the EOR is doing the design than everything should be shown.

I have to disagree with this. When delegating a design, it is incumbent on the EOR to provide reasonable structure for the metal studs to function efficiently. Would you send out a job where the metal studs have to frame out a 40' wide window? Sure it could be done, but it would be ridiculously inefficient.

 

[sandman21]

I have delegated metal stud jobs with large openings. I made sure that the architect had a soffit to allow framing to be added. I did not show of design the soffit or the framing in the area as it was to be built to the specs. You are attempting to create a situation where an item is unbuildable, a far different situation than the delegated engineer needing to provide support for metal framing. In the case of a window with no support the architect will need to correct the situation.

 

[Ron]

To clarify....shame on me for not proofing!.....formation was meant to be "information".

 

[XR250]

In the case of a window with no support the architect will need to correct the situation.

The problem is where do they draw the line. It certainly depends on the EOR, Arch and GC. Often times, their attitude is , "You bid it, you build it". The current job I am working on is so wrought with BS like this I am losing my mind. I have an area with 3 5/8" exterior wall studs to span 21 ft. Sure, I can make it work, but it is a bunch of 12ga studs tightly spaced. They are unwilling to make changes to allow 6" studs in this area.

 

[Teguci]

I thought this link is appropriate regarding delegated designs (The EOR and a precast filigree fabricator/engineer). In particular, this statement:
"11.The structural engineer relied heavily on the filigree fabricator for the structural design of the exterior bay between grid line 1 and 4, levels P4 thru PS. The structural engineer did not conduct independent structural calculations to proportion the negative reinforcements, shear reinforcement, and potential torsion on the exterior beam. The responsibility of the design rested solely with the structural engineer of record."

and

"12.The structural drawings lacked clarity."

https://www.osha.gov/doc/engineering/2003_10.html

I could see similar statements being leveled at an EOR who didn't provide sufficient load path detail. For instance "The structural engineer relied heavily on the light gage steel fabricator for the structural design of the exterior walls. The structural engineer did not ... The responsibility of the design rested solely..."

 

[sandman21]

That case is not the same as we are discussing.
From section 6;
"The responsibility of design of all structural members, other than precast filigree members, must rest with the structural engineer of record."

The SEOR did not provide the structural members necessary to support delegated designed component. Instead relied on the delegated designed component manufacturer for structural engineering on structural components.

Needing to provide heavy gauge closely spaced studs is not the same as the arch. having 60' 3 5/8" studs.

 

[jayrod12]

although I agree those are two different cases. I think what separates the good from bad EORs is their ability to avoid solutions that are outside the norm. This includes preliminary sizing of steel studs to have something reasonable work. If the arch is showing 3 5/8" steel studs spanning 20 feet that's dumb, and the EOR should point that fact out to them early on. It makes the entire construction process easier.

Obviously the days of zero change projects appears to have gone the way of the dodo bird, but that doesn't mean it's something we shouldn't strive for. I strive for zero RFI projects (haven't come close yet but it's still my goal). I also feel that you can't be a good EOR unless you've done your share of delegated work so you understand what should and should not be included in a good set of structural drawings.

 

[XR250]

Very nice, Jayrod.
Thanks